The invention concerns a connecting device for the connection of a first workpiecexe2x80x94provided at least with one undercut longitudinal groovexe2x80x94to a second workpiece which is in turn provided with a longitudinal groove or grooves, wherein the connecting device is at least of an extent which exceeds the width of the narrow cross-section of the longitudinal groove or grooves; in particular the connecting unit is to be used in relation to profile bars of polygonal cross-sectionxe2x80x94preferably in relation to extruded profile members of rectangular cross-sectionxe2x80x94with longitudinal grooves extending in the side walls of the profile members.
The specification of the applicant""s DE-U 92 12 696 discloses a nut-like element as a connecting device, which in particular is used in relation to hollow profile members which are extruded from light metal and the internal space of which is not accessible from the exterior. That previously known element is admittedly of a parallelepipedic configuration and has at least two mutually oppositely disposed flank walls which are inclined at an angle, as well as a spring member which on the one hand bears fixedly against one of the inclined flank walls and which on the other hand engages with its free end over the narrower surface of the element; in the relaxed condition of the spring that end is arranged at a spacing relative to the element. When the spring member is pressed against the nut element, the latter can be readily insertedxe2x80x94with its narrow side leadingxe2x80x94into the groove of the undercut configuration.
The applicant""s DE-U-297 17 089 also discloses for hollow profile members with longitudinal grooves which open towards the end of the profile member, a connecting device in the form of a loop-shaped clamping connector which has loop limbs projecting approximately at a right angle at both ends from a base plate; at the transition of the base plate, side slots on both sides delimit a central limb neck configuration. An angular clamping connector which is also described therein is provided at one end of a base plate with a loop limb which projects approximately at a right angle; in this case also side slots at both sides delimit at the transition of the base plate a central limb neck configuration.
In consideration of those systems, it is the object of the invention to provide a further fixing option for pairs of, in particular extruded hollow profile members of polygonalxe2x80x94in particular rectangularxe2x80x94cross-section. The invention seeks to provide that this connecting device can be fitted quickly and easily and is very substantially resistant to rotation.
That object is attained by providing a connecting device for the connection of a first workpiece provided with at least one undercut longitudinal groove to a second workpiece which in turn is provided with a longitudinal groove or grooves, wherein the connecting device has at least one extent which exceeds the width of the narrow groove cross-section of the longitudinal groove or grooves, in particular a connecting device for profile bars of polygonal cross-section with longitudinal grooves extending in the side walls of the profile members, characterised in that the connecting device has at least one main body which can be partially fitted into the narrow cross-section of the longitudinal groove and which has longitudinal lateral shoulder surfaces extending on both sides of a ridge bar or the like central portion, which in the region of the ridge bar has passing therethrough at least one pin-like connection member which is adapted to be connected to the workpiece or the profile bar, wherein the connecting device outside the main body is provided with a connection element for the other workpiece. The scope of the invention also embraces all combinations of at least two of the features disclosed in the description and the drawing.
In accordance with the invention the connecting device has at least one main body which can be partially fitted into the narrow groove cross-section of the longitudinal groove, with longitudinal lateral shoulder surfaces which extend on both sides of a ridge bar or the like central portion and which in the connecting position bear against the inside of shaped rib grooves, which main body in the region of the ridge bar has passing therethrough at least one pin-like connection member which is adapted to be connected to the workpiece or the profile bar; the connecting device is additionally provided outside the main body with a connection element for the other workpiece.
In a preferred embodiment of the connecting device at least one of the ends of its ridge bar, the main body is provided with a shoulder surface which transversely connects the longitudinal lateral shoulder surfaces, as a support surface for a clamping block which can be fixed thereon. Its width and the width of the ridge bar are to correspond to the width of the slot of the longitudinal groovexe2x80x94that is to say the region of the groove which is not undercutxe2x80x94so that those parts of the connecting device can be introduced into same.
If there is a wish to connect to the one workpiece or profile member a second workpiece with axe2x80x94preferably centralxe2x80x94bore-like passage, at a right angle, then the pin-like connection member which projects from the ridge bar of the main body is introduced into that passage and fixed therein.
For that purpose, it has proven to be desirable for the connection member to be in the form of a screw pin with two screwthreaded regions which are preferably to be provided with opposite screwthreads and/or which are to be of different diameters. The latter measure facilitates in particular orientation upon assembly; the screwthreaded region of smaller diameter is associated with the main body which affords the corresponding screwthreaded bore. The same purpose can be served by the measure of providing that the longitudinal-side shoulder surfaces extend in displaced relationship in respect of height by a distance in relation to the transverse shoulder surface or surfaces.
In accordance with the invention at least the screwthreaded region which projects outside the main body is provided with a self-forming thread so that it can be firmly introduced into the counterpart workpiece in the event of the counterpart workpiece having a smoothxe2x80x94that is to say thread-lessxe2x80x94passage.
In order to permit movement of the clamping block in the longitudinal direction of the connecting device, a guide leg for a groove of the clamping block projects from the transverse shoulder surface; the groove is advantageously of an undercut configuration in cross-section and the guide leg is of a corresponding cross-section. However, the clamping block can also be connected to the main body by a screwxe2x80x94which is possibly provided in inclined relationshipxe2x80x94and may have inclined corner regions at its underneath surface, parallel to the longitudinal side shoulder surfaces.
The two clamping blocks which are movable in the longitudinal direction of the workpiece or the profile bar engage into the longitudinal groove of the profile bar and thereby provide a means for preventing rotation thereof. The element is pushed into the longitudinal groove of the profile bar and fixed at the desired position by tightening the screws in the clamping blocks. The described connection can be released at any time and can be moved in the longitudinal direction of the second profile bar. In that situation, the two profile bars remain undamaged; the connection thereof does not involve any mechanical processing treatment. The screw in the clamping block, by engaging into the guide bar of the main body, prevents it from falling out. When the screws are firmly tightened however a bracing effect is produced in the groove of undercut configuration. Inclined positioning of the screws in the clamping blocks is advantageous so that the pressure points are as close together as possible.
In another connecting device, in accordance with the invention, formed on the main body thereof at one end is a hammerhead-like insertion element, by means of a neck which is on the center line of the main body; in this arrangement the spacing of the flank surfaces of the hammerhead from the center line is to be greater than the spacing thereof from the side edges of the main body. The hammerhead is inserted into the undercut longitudinal groove in the workpiece which is associated with the profile member or workpiece for receiving the main body.
It has proven to be desirable if in this case a screw pin passes through the main body, which screw pin can be inclined at an angle relative to the surface of the main body. That screw pin should be inserted beneath or outside the underneath surfaces of the main body into axe2x80x94also inclinedxe2x80x94notch in the deepest part of the longitudinal groove which accommodates the main body; that notch is to be previously produced without any difficulty by means of an auxiliary tool and the position thereof can be freely selectedxe2x80x94depending on the respective factors involvedxe2x80x94upon assembly.
The screw pin, preferably a grub screw, is first screwed in after the connecting device has been pivoted into position and is then between the shoulder surfaces whichxe2x80x94as statedxe2x80x94bear against the inside of the longitudinal groove. When the screw pin is tightened the connecting device is urged upwardly and at the same time with its stepped cross-section into the longitudinal groove of the profile member. In that procedure on the other hand the hammerhead pulls the second profile member against the end face of the first profile member. A prerequisite in that respect is the above-mentioned provision of the notch at a precise spacing relative to the end face at the deepest part of the groove in the first profile member.
The scope of the invention also embraces a further design configuration in the form of a plate-like or strip-like main body through which, near the end faces thereof, passes at least one respective screw pin; they are preferably inclined relative to each other, in which case their tipsxe2x80x94which engage into notches at the deepest part of the groovexe2x80x94are closer to each other than their actuating ends which are above the main body. By virtue of that feature, a pulling force is applied to two workpieces or profile members with aligned longitudinal grooves which jointly receive the main body, in other words, the end faces thereof are pressed against each other.
As already set forth above, the main body is inserted at the end into the longitudinal groove of the first profile member and lightly fastened with the one screw pin. The second profile member is then fitted in aligned relationship at the end on to the first profile member, being guided by the main body. The screw pins are now firmly tightened, in which case the main plate is urged upwardly into the groove in the two profile members and at the same time the two profile members are braced against each other.
In this case also the notches are produced with a simple auxiliary tool; the screw pins are securely held therein.
The following have been found to constitute particular advantages of the connecting system according to the invention:
no machining treatment required;
quick and easy assembly;
a connection which is force-locking and secured to prevent rotational movement;
potential compensation by virtue of notch edges;
no external damage to the profile member, and
subsequent installation is possible.